In the security inspection field, it is very important to detect dangerous articles, such as narcotic drugs, explosives, chemical warfare agents, industry poisonous agents. Therefore, various detectors for detecting the above articles have been developed. However, for each kind of detector, samples have to be transferred from a detecting surface of the article into the detector during detecting.
At present, two methods of a suck-type sampling method and a wipe-type sampling method are commonly used. In the wipe-type sampling method, sampling is performed by using a wiping paper to wipe the detecting surface, and then the wiping paper is moved directly into a detector. However, the present application is directed to the suck-type sampling method rather than the wipe-type sampling method. In the suck-type sampling method, sampling is performed directly at the detecting surface by way of sucking, or is performed based on collected samples in advance by way of sucking.
There are mainly two suck-type sampling methods used in existing products or disclosed by published patents. The first method is a direct suction method in which, as shown in FIG. 1, a detecting device sucks air directly from surrounding environment. Because some dangerous articles have viscosity, they tend to adhere to surfaces of an object to be detected. Thus, the direct suction method can only capture volatilized gases or fine particles in a free state. In order to collect the dangerous articles adhered to the surfaces of the object to be detected, a second method is widely used, in which airflow is first blown to raise the particles of the sample; then, the raised particles are sucked into the detecting device, as shown in FIG. 2. Advantageously, the blown airflow is formed of spiral or heated air.
FIG. 2 shows an example of the second method which improves the detecting efficiency; usually, the airflow is blown from peripheral of a sampling device and is sucked at a center part thereof. The above method can be implemented more easily with a sampling device, wherein the inlet of a detecting device is commonly provided at the center part of the sampling device so that the detecting device can be connected directly with the sampling device. However, because an air exit has a large size while the airflow is sucked at the center part, the blowing force of such sampling device is small, which results in a low sampling efficiency.